Process for separating nitroglycerine from residual acids



Feb. 6, 1934. A. SCHMID 1,946,414

PROCESS FOR SEf'ARATING NITROGLYCERINE FROM RESIDUAL ACIDS Filed Jan. 25, 1928 2 Sheets-Sheet l INVENTOR.' A. Sc/777w'a A TTORNEYS.

Feb. 6, 1934. sc m 1,946,414

PROCESS FOR SEPARATING NITROGLYCERINE FROM RESIDUAL ACIDS Filed Jan. 25, 1928 2 Sheets-Sheet 1 N V EN TOR. A Sch m k? A TTORNEYS.

Patented Feb. 6, 1934 PROCESS FOR SEPARATING NITROGLYC- ERINE FROIH RESIDUAL ACIDS Arnold Schmid, Vienna, Austria; Hans Schmid and Irma Schmid, administrators of Arnold Schmid, deceased, assignors to Karl Schmid,

Mannheim, Germany Application January 25, 1928, Serial No. 249,474, and in Germany February 5, 1927 1 Claim.

In nitration apparatus there is formed an emulsion of nitroglycerine and residuary acid during the production of nitroglycerine. The

acid is not wholly separated in the usual separating devices and small quantities of nitroglycerine separate from the acid during the fol lowing days, so that a subsequent separation has to take place. Generally the same is carried m out in very large vessels, in which the acid is 15 quence of necessary repairs on large apparatus.

Many proposals have been made already in order to avoid or shorten the time of the subsequent separation, but all these known processes possess many drawbacks. It is already known to add water but thereby the nitroglycerine of the subsequent separation is lost, or the proposal has been made to use oxidizable additions, which render the process more difiicult and dangerous.

Contrary to these known chemicai methods, the subsequent separation and if desired also the initial separation can be greatly expedited by means of the apparatus according to the present invention. It has been discovered, that during the subsequent separation a chemical reaction does not take place in the acid, but solely a mechanical break-down or" the fine emulsion. It has been discovered also, that the speed of the operation increases if the film of the liquid in which the same is carried is thin. This depends on the reduction or" the time and extent of raising of the small drops of nitroglycerine.

This discovery has been utilized in the apparatus according to the present invention.

The simplest solution is to make the vessel for carrying out the subsequent separation of small height, fiat shape or comparatively long tubular shape. Such a vessel takes up a great deal of space. Another construction is to sub-divide a receptacle of any convenient cross-sectional .area into low compartments by means of hori- "invention is adapted for intermittent as well as for continuous operation.

Two modes of carrying out the present invention are illustrated by way of example on the accompanying sheets of drawings in which:-

Fig. 1 shows an apparatus adapted for continuous operation in longitudinal section and Fig. 2, a transverse section along line 22 of Fig. 1.

Fig. 3 illustrates a modified construction of the apparatus in side view, partly in section, and Fig. 4, a transverse section along line 4-4 oi Fig. 3.

As shown in Figs. 1 and 2, the receptacle 1 is in the shape 01' an inclined prism and provided with plates 2, which are arranged parallel with respect to one another and to the floor 3 of the receptacle. The separation takes place in the fluid-layers 4 between the said plates. The emulsion to be separated is admitted by way of the funnel 6 and continuously passes through the intermediate spaces of the films 4, where the last traces of the nitroglycerine are separated very rapidly. The overflow tubes 7 and 8 for the nitroglycerine or the residuary acid are ar ranged in such a manner, that the separating level is fairly high and visible through the observation glass 9.

An improvement in the apparatus consists in that the plates are provided with longitudinally and transversely disposed grooves or are corrugated as shown in Fig. 3. In this event the small drops of nitroglycerine accumulate at the base of the grooves at the underside of the plates and there they are united far quicker than on the smooth surface. In every one of these lines a thin thread of nitroglycerine moves along the plates 2 which by Way of a small opening at 10 can move upward from film to film.

A further improvement of the apparatus consists in the provision of screens 11. In the construction according to Fig. 1, the free spaces permit an imperfect distribution of the liquidcurrent only. The greatest part of the residuary acid passes too quickly between the top plates and is not sufficiently freed of the nitroglycerine, while at the bottom the current is very weak and also in the middle of the apparatus the acid is retained for too long.

In the apparatus according to Figs. 3 and 4, the acid entering through the funnel 6 cooperates with the first screen 11 disposedv in the conical head 12 of the receptacle. This screen is provided with a few large holes near its periphery, so that the liquid-current is divided into a number of currents. The holes in the second screen are smaller and more numerous and displaced with respect to the holes in the first screen, so that each or the said currents is again divided. This procedure is repeated as soon as the divided currents meet the third screen, provided with still smaller and more numerous holes,

layers communicating with each other at each end, whereby the nitroglycerine as it separates may pass upwards along the under surfaces of the division plates toward the top of the body of liquid where it is continuously drawn off, while the separated acid flows down the plates toward the lower portion of the vessel where it is discharged continuously.

ARNOLD SCHMID. 

